Retorting and coking of bituminous solids



GASEOUS PRODUCTS 9 P u .5 M L 7 EA SW \KG R Y m am r E m um m n E m N mm N c E s M 0 29:17:55 u s T Vm T O s A c T N c E N T HR O S N W M A m B u m 6 mm o o L w 8 WR P O N A R J 2 AA Z w G P DR E Y I GN Y 0 0 B c A 8 N E 9 B U 2 R 5 N T IT L QA G D 7 l N\ LA C\ 6 UR E Y 2 T 0 0E Y I L 6 H G W C OH R 3 7 N 2 m m 2 CM R \G5 I 5% H R O H P 1 AS HA 56 May 2, 1961 J. w. scoT'r, JR

RETORTING AND coxmc OF BITUMINOUS SOLIDS Filed Sept. 30. 1958 FRESH SHALE SPENT SHALE E E L m L P 7 N TGQ A R A 1v 3 mi mm 6 H as w. T. K s 4 S KN UE R E EE OR RBN RON USIVICU A O L B TRz w Fe w M J u T N 9 S Om w o 3 I. c D F OUT United States Patent 2,982,701 RETORTING AND COKING OF BITUMINOUS SOLIDS John W. Scott, Jr.,' Ross, Calif assignor to California Research Corporation, San Francisco, Calif., a corporation of Delaware 7 Filed Sept. 30,1958, Ser. No. 764,362

3 Claims. (Cl. 202- -6) "unit in which the retorting itself is accomplished, then such a coking operationwould be very desirable. It is an object of the present invention to provide such means.

In accordance with the present invention, the foregoing desirable objectives may be accomplished in the operation of a bituminous solids retorting system wherein downwardly moving comminuted solid particles. are brought to retorting temperatures by counteroun'ent contact with a hot gaseous retorting medium in a retorting zone from which normally gaseous and normally liquid hydrocarbons are produced and recovered from the retorted solids. In connection with such a system, an integrated coking operation may be effected by separating a heavy fraction (commonly referred to as a tar stream) from the liquid hydrocarbons so produced, preheating 'this tar stream to a temperature of from about 600 to a 900 F,, distributing this preheated tar stream over said downwardly-moving particles during passage of saidparticles through a distribution 'zone' located ahead' of said retorting zone, and preheating the solid particles entering said distribution zone to temperatures of at least 900 F., and preferably in the range 900 F. to 1500 F. For effective coking operation, the bituminous'solid particles should be introduced into the distribution zone at a rate of at least 7 pounds of solids per pound of .preheated tar stream. Under these conditions, the product efiluent of the retorting zone will contain the hydrocarbon products of decomposition of the introduced tar stream along with the hydrocarbons retorted from the bituminous solids.

The process of the present invention will better be understood from the following description of a specific embodiment thereof, when read in connection with the accompanying drawing in which the single figure there shown is a diagrammatic illustration of a preferred embodiment of apparatus and flow paths for use in practicing the invention. I

Referring now to. the drawing, particles of oil shale, for example, colorado shale' which may contain about 30 gallons of shale oil per ton, having a size in the range ?%-inch to 2-inch in diameter, are passed through line 1 into housing 2, which contains shale heating zone 3, tar" distribution zone 4, retortingzone 5,.and'shale cooling and preheating zone 6. Burners 7, supplied through line;

8 with an oxygen-containinggas, are located in the moving shale bed near the lower end of retorting-zone 5 2,982,701 Patented May 2, 1961 Combustible .gases entering'housing 2 from line 9 rise upwardly through the shale bed, generally in countercurrent contact with the'downwardly moving solids in the shale bed, and a portion of these gases is burned in burners 7, the resulting rising hot combustion products accomplishing retorting of the shale in retorting zone 5. These rising hot combustion products serve further to preheatthe colder incoming shale in shale heating zone 3. Retort products comprising vapors and fogs of the kerogeniccomponents of the shale are withdrawn from housing 2 through line 10, and are passed to gas-liquid separator 15, from which gases are withdrawn through line 16 and liquids are passed through line 17 to distillation zone 18. Light liquid products may be withdrawn from distillation zone 18 through line 19. A net production of gaseous products may be withdrawn through line 20 if desired. Combustible gases are recycled through line 9 to shale cooling and gas preheating zone 6, as previously described. The gases in line 9 may be augmented, if desired, by combustible make-up gases introduced into the system through line 25.

A heavy hydrocarbon fraction is passed through line 26, pump 27, and oil heating furnace 28, to the moving shale bed in housing 2. This heavy fraction is heated in furnace 28 to a temperature in the range of about 600 to 900 F., prior to its introduction into tarv distribution zone 4 located in the movingshale bed. Tar distribution zone 4 serves to distribute the heavy hydrocarbons or tar entering tar distribution zone 4 through line 26 evenly over the shale particles in the descending shale bed. This distribution may be accomplished by conventional means, for example by passing the descending shale particles over a conical member over which they tumble in a, thin layer while being evenly coated with the tar froni line 26. Ithas been found that, in order to prevent cementing of the shale particles and other disadvantages, there must be maintained, in tar distribution zone 4 a flow ratio of at least 7 pounds of shale, orother bituminous solids, per pound of the pre-' heated heavy hydrocarbons entering tar distribution zone 4fthrough line 26. p

Concurrent flow coking zone 29 is provided at the upper end of retorting zone 5 to provide a suflicient residence time of the'tar on the shale particles to insure adequate coking." Because this would be prevented if all of the rising hot gases from retorting zone 5 were permitted to pass upwardly through tar distribution zone 4, thereby sweeping upwardly much of the tar before it had been sufiiciently long in residence on the shale particles to become adequately coked, at least a substantial portion of the rising hot gases is passed from retorting zone 5 through line 30 to shale heating zone 3. In this manner these rising hot gases, after having served to accomplish retorting in retorting zone 5 are made to by-pass concurrent fiow' coking zone 29 and tar distribution zone 4 and are prevented from impeding proper operation of these latter two zones. It will be noted that the function of these rising hot gases inheating the cooler saryto maintain in tar distribution zone 4 the necessary flow ratio of 'at least 7 pounds of shale or other bituminous solidsflper poundof; tar entering tar distribution zone 4 through line 26. Spent shale that is not sorecycled may be withdrawn from the system through line 35.

While not indispensable to the operation of the present" invention,it-,may in some cases be. desired to withdraw a portion of the retorted shale from retorting zone through line 38 and pass it to a coke burner 39, supplied with an oxygen-containing gas through line 40. In coke burner 39 carbon can be burned from the particles of retorted shale to provide those shale particles with additional heat which they may carry back to the shale cooling and gas preheating zone 6 through line 45. Flue gases may be withdrawn from coke burner 39 through line 46.

In the operation ofthe above embodiment the burners 7 either may be located within the moving-shale bed asshown or they may be located in a separate burner external to housing 2. in either case, all of the rising hot' gases from shale cooling and gas preheating zone 6 may be passed through burners 7 or only a portion thereof may be heated. In the latter case, the portion of the rising gases passed throughbu'rners '7 may be passed aroundvbur'ners 7 directly to retortingzone 5. g

It will also be noted that if tar entering. tar distribution zone 4 through line 26 were swept upwardly into contact with the colder shale in shale heating. zone 3,- the tar would condense in zone 3, some would reflux downwardly, and destroy the eficacy of the process. To the contrary, coking zone 29 provides a concurrent flow for shale particles, tar, and 'vapors,'thus assuring sufficient residence time in zone 29 for adequate coking to be accomplished.

The foregoing is by way of illustration only, and the,

only limitations intended are those in the appended claims.

What is claimed is:

1. In a process for recovering liquid hydrocarbons from particulate-form bituminous solids, which comprises passing a moving bed of said solids through a retorting zone, retorting said solids in said retorting zone in countercurrent contact with a heated combustion gaseous retorting medium, withdrawing from said retorting zone hydrocarbons retorted from said solids, separating the withdrawn hydrocarbons retorted from said solids to recover combustible product gases and a liquid hydrocarbon product, and recycling at least a portion of the recovered combustible product gases to a lower portion of said retorting zone for combustion therein, the improvement which comprises preheating a heavy portion of said liquid hydrocarbon product to a temperature in the range of about 600 to 900 F., further decomposing said preheated heavy portion to produce therefrom lighter liquid and gaseous products and coke by returningto said bed and distributing said preheated heavy portion in a distribution zone in said bed over moving particles of said bituminous solids prior to passage of said solids through said retorting zone, maintaining said particles of bituminous solids passing through said distribution zone at a temperature of at least 900 F., maintaining in said distribution zone a ratio of at least seven pounds of bituminous solids per pound of said preheated heavy portion, and withdrawing from said retorting zone hydrocarbon products of decomposition of said preheated heavy portion along with said hydrocarbons retorted from said solids.

2. Process as in claim 1, wherein the temperature of said particles of bituminous solids in said distribution zone is about from 900 to 1500 F.

3. Apparatus for recovering liquid hydrocarbons from particulate-form bituminous solids, which comprises an elongated vertical housing for a moving bed of said solids, said housing containing, in descending order, a solids heatingfzone, a heavy liquid hydrocarbon distribution zone, a retorting zone, and a solids cooling zone, said retorting zone containing a concurrent flow coking zone at the upper end thereof immediately below said'distribution zone, combustible gas burners for supplying hot gaseous combustion products to a lower portion of said retorting z'one,',a' gas by-pass around} said cokingv zone and said tar distribution zone from a lowerportion of said coking zone to said solids heating zone, means for passing said solids downwardly through said housing and the zones therein, means for introducing into said [distribution zone heavyhydrocarbons to be wired in said coking zone, means for withdrawing product vapors from said solids heating zone of said housing, means for sepa' rating product gases fromsaid vapors, means for recy cling at least a portion of said product gases to said solids cooling zone, means for passing. said recycled product gases upwardly to said gas burners. and to said retorting zone, and means for withdrawing spent solids from a lower portion of said housing.

ReferencesCited in the file of this patent UNITED STATES PATENTS 7 1,908,133 Egloflf May 9, 1933 1,963,264 Eglofi et a1, June 19, 1934 "2,131,702 Berry Sept. 27, 1938 2,406,810 Day Sept. 3, 19.46

2,610,944 Hemminger Sept. 16, 1952 2,885,338

Evans May 5, 1959 

1. IN A PROCESS FOR RECOVERING LIQUID HYDROCARBONS FROM PARTICULATE-FORM BITUMINOUS SOLIDS, WHICH COMPRISES PASSING A MOVING BED OF SAID SOLIDS THROUGH A RETORTING ZONE, RETORTING SAID SOLIDS IN SAID RETORTING ZONE IN COUNTERCURRENT CONTACT WITH A HEATED COMBUSTION GASEOUS RETORTING MEDIUM, WITHDRAWING FROM SAID RETORTING ZONE HYDROCARBONS RETORTED FROM SAID SOLIDS, SEPARATING THE WITHDRAWN HYDROCARBONS RETORTED FROM SAID SOLIDS TO RECOVER COMBUSTIBLE PRODUCT GASES AND A LIQUID HYDROCARBON PRODUCT, AND RECYCLING AT LEAST A PORTION OF THE RECOVERED COMBUSTIBLE PRODUCT GASES TO A LOWER PORTION OF SAID RETORTING ZONE FOR COMBUSTION THEREIN, THE IMPROVEMENT WHICH COMPRISES PREHEATING A HEAVY PORTION OF SAID LIQUID HYDROCARBON PRODUCT TO A TEMPERATURE IN THE RANGE OF ABOUT 600* TO 900* F., FURTHER DECOMPOSING SAID PREHEATED HEAVY PORTION TO PRODUCE THEREFROM LIGHTER LIQUID AND GASEOUS PRODUCTS AND COKE BY RETURNING TO SAID BED AND DISTRIBUTING SAID PREHEATED HEAVY PORTION IN A DISTRIBUTION ZONE IN SAID BED OVER MOVING PARTICLES OF SAID BITUMINOUS SOLIDS PRIOR TO PASSAGE OF SAID SOLIDS THROUGH SAID RETORTING ZONE, MAINTAINING SAID PARTICLES OF BITUMINOUS SOLIDS PASSING THROUGH SAID DISTRIBUTION ZONE AT A TEMPERATURE OF AT LEAST 900* F., MAINTAINING IN SAID DISTRIBUTION ZONE A RATIO OF AT LEAST SEVEN POUNDS OF BITUMINOUS SOLIDS PER POUND OF SAID PREHEATED HEAVY PORTION, AND WITHDRAWING FROM SAID RETORTING ZONE HYDROCARBON PRODUCTS OF DECOMPOSITION OF SAID PREHEATED HEAVY PORTION ALONG WITH SAID HYDROCARBONS RETORTED FROM SAID SOLIDS. 